The present invention relates to acoustic technology. More specifically, the present invention relates to a microphone which may be configured by the user for both unidirectional and omnidirectional operation.
Speaker phones employ a microphone and a loudspeaker to allow a single user to engage in a telephone conversation with his hands free, or to allow several people in one location to participate in a conversation using a single phone. Such phones typically incorporate a particular type of microphone depending upon the application for which they are intended. For example, a speaker phone intended for use by a single person typically employs a unidirectional microphone which is designed to pick up acoustic energy from the hemisphere in front of the microphone much more efficiently than from the hemisphere behind the microphone. This reduces the room echo which often results in the impression that the user is speaking from a barrel. Moreover, by properly positioning the unidirectional microphone, coupling from the loudspeaker and the resultant instability are reduced.
In contrast, a speaker phone intended for conferencing must be able to pick up acoustic energy from several different vantage points such as, e.g., from several people seated around a conference table. Therefore, such phones typically employ multiple unidirectional microphones pointed in different directions. However, while these microphones may be positioned to reduce loudspeaker coupling as mentioned above, sound performance is degraded by room echo which is picked up by opposing microphones. Moreover, having multiple microphones increases the cost of such phones undesirably.
It is therefore desirable to provide a less expensive alternative to the multiple microphone speaker phone which realizes the performance advantages of the single unidirectional microphone device when employed by a single user and which also is capable of being employed in the conferencing context.